In a process of receiving sound waves by human ears, the auricle, the ear canal, the skull, the shoulder, and the like may reflect and diffract the sound waves, and then the sound waves are conducted to the ear drum and perceived by brain nerves. All these have certain impact on sounds heard by the human ears. In acoustics, such impact is described by using a head related transfer function (HRTF). Therefore, the human brain can determine a position and a distance of an emitted sound according to experience. Based on this, in recent years, a more advanced simulated human head recording technology has been increasingly more favored in the field of audio recording.
In short, the simulated human head recording technology means that two micro omni-directional microphones are placed in positions close to ear drums in ear canals of an artificial human head that is almost the same as a real human head, so as to simulate an entire process of hearing sounds by the human ears. The artificial human head has auricles, ear canals, a skull, hair, and shoulders, and even skin and bones are also made of materials most approximate to human body materials, so as to simulate as really as possible impact exerted by all HRTFs on the human ears when hearing sounds.
Signals recorded by such two microphones are equal to sounds heard by both ears of a real person at the position of the artificial human head, the impact of all the HRTFs in the recording process are recorded and can be restored and replayed. Sounds recorded in this manner can almost perfectly restore a sound field at 360 degrees of a recording site as if a hearer is on the recording site. Certainly, during playing, a good stereo effect can also be achieved by playing the sounds with a loudspeaker, but is incomparable to that of an earphone, because in the process of playing the sounds with the loudspeaker, a listener is subjected to impact of the HRTF once again, and original HRTF information in a disk is disturbed.
In addition, with the development and popularization of a virtual reality (VR) panoramic video technology, a visual angle of a picture is changed by means of head tracking, so that a visual system and a motion perception system of a user are connected, and the user can observe a presented scene through head motion. A VR panoramic video device enables the user to watch a video at any visual angle within 360 degrees. In order to bring stereo perception experience to users by using the VR panoramic video technology, an audio recording technology in a panoramic video also becomes a focus, and combining the simulated human head recording technology and the VR panoramic video technology becomes a new research direction.
An audio recording device used in an existing VR panoramic video technology has many limitations, not only a sound source is single, but also tone quality is flat and non-stereoscopic, a real sound field cannot be restored, and a requirement for high-quality panoramic audio in the VR panoramic video technology cannot be met.